Electromagnetic valve for regulating the flow-rate of melt from a container

ABSTRACT

The outflow rate of molten metal from a furnace or ladle is regulated by a multiphase electromagnetic valve surrounding an outlet of the furnace or ladle.

United States Patent [1 1 Sundberg et a1.

11] 3,767,090 1 Oct. 23, 1973 ELECTROMAGNETIC VALVE FOR REGULATING THE FLOW-RATE 0F MELT FROM A CONTAHNER Inventors: Yngve Sundberg; Erik Svensson,

both of Vasteras, Sweden Allmanna Svenslka Elektriska Aktiebolag, Vasteras, Sweden Filed: Jan. 18, 1971 Appl. No.: 107,222

[73] Assignee:

[30] Foreign Application Priority Data Jan. 20, 1970 Sweden 623/70 U.S. Cl. 222/383, 417/50 Int; Cl B2211 37/00 Field of Search 222/DIG. 2, DIG. 15,

[56] Reierences Cited UNITED STATES PATENTS 3,263,283 8/1966 Allard 417/50 X 2,707,718 5/1955 Tawa 417/50 X 2,541,841 2/1951 Tama 417/50 X 3,008,418 11/1961 Blake 417/50 3,005,116 10/1961 Reece 417/50 X Primary Examiner-Robert B. Reeves Assistant Examiner-David A. Scherbel Attorney-Kenyon & Kenyon Reilley Carr & Chapin [57] ABSTRACT The outflow rate of molten metal from a furnace or ladle is regulated by a multiphase electromagnetic valve surrounding an outlet of the furnace or ladle.

4 Claims, 2 Drawing Figures ELECTROMAGNETIC VALVE FOR REGULATING THE FLOW-RATE OF MELT FROM A CONTAINER BACKGROUND OF THE INVENTION Swedish patent application No. 7147/69 (U.S. Pat. application No. 34,988) describes a furnace or ladle for melt having an outlet extending upwardly from its bottom at an angle from the vertical. Around the tubular outlet is an electromagnetic valve which regulates the flow of melt through the tube with regard to the output signal from a level or weight indicator of an intermediate ladle. The mouth of the tube is on a level considerably above the bottom of the container.

There are considerable problems in designing the valve/pump in such a way that an effective pump or valve action is obtained on the melt in the outlet so that the tapping can be stopped or controlled effectively, for example regulated from a level or weight gauge in a casting ladle or intermediate ladle, for example in continuous casting (See the above-mentioned specification).

SUMMARY OF THE INVENTION This invention is a solution to this problem, amongst others, and is characterized in that the electromagnetic pump/valve is provided with one or more coils, the ratio between the pole distribution (1-) and the diameter (d) being-between 0.8- and2.0.

THE DRAWINGS The invention is further exemplified in the accompanyings in which FIG. 1 shows an outlet in a blast furnace, seen partly in section, and

FIG. 2 a two-pole electromagnetic pump/valve.

PREFERRED EMBODIMENT FIG. 2 shows an electromagnetic pump or valve for the transport of melt in the outflow direction (in cooperation with hydrostatic pressure) and the opposing melt tapping (in opposition to hydrostatic pressure). The pump consists of four part-coils A-D, two-phase fed. The pole distribution is shown at 1 and the coil diameter at d.

FIG. 1 shows a blast furnace, steel furnace, ladle or other container 11 for melt having at least one tapping openingl2 at the bottom, for example in the form of upwardly directed pipes, surrounded by the electromagnetic, multiphase fed pump or valve 13, 14. When tapping is to'be decreased the phase sequence and thus the moving field is directed in towards the container 11 (valve). -When tapping is to be increased, this field is decreased or reversed and the melt in the outlet 12 is accelerated (pump) and tapping is carried out into a casting means near the arrow A (chill, casting mould, for example for continuous casting, intermediate ladle, for example provided with level gauge or scales, etc.).

In order to achieve the greatest possible valve or pump action, according to the invention the multiphase coils 13 (one or more in number) of the electromagnetic pump/valve are given such pole distribution 1-, that the ratio between the pole distribution and the coil diameter (d) is 'r/d 0.8 2.0.

The definition of pole distribution 1' and the diameter are clear from FIG. 2 which shows a two-pole, twophase fed electromagnetic pump. One phase is connected so that at every moment a plus and a minus partcoil (A, C) is obtained and the distance between their magnetic centres is 'r. The same is true for the other phase with its part-coils (B and D). The winding can be made more mixed or less and the pole number can be varied from two and upwards. The pump may have several consecutive coils to cover the required transport distance, in which case the coils are suitably multipole connected.

The coils are surrounded in the conventional manner by one or more iron cores 14. The outlet is dimensioned so that its diameter, i.e., the diameter of the melt in this (not the same as d) is between 0.1 Hand 0.3 {E where p is the resistivity of the melt in ohm mm /m. (m is the length of melt in the outlet tube 12).

In order to decrease the heat losses in and about the outlet an electrically conducting tube 15 is inserted be tween coils and tube (melt). During feeding of the pump coils currents are induced in this tube under the influence of the field from the coil(s) 13 so that this is heated and heat losses from the metal in the tube 12 (the pump) are counteracted.

The invention can be varied in many ways scope of the following claims.

We claim:

1. Means for regulating the speed of melt flowing out of a container, comprising a multiphase electromagnetic valve pump arranged around an outlet in the container, said outlet being an upwardly directed tube, leading from the lower part of the container to a level below the highest possible melt level in the container, said valve pump being arranged around the tube and its coil being fed with multi-phase AC voltage with switchable phase sequence, the direction of the phase sequence being controlled from the output from measuring means for measuring the amount of melt, said valve pump comprising at least two sectioned coils, the ratio between the pole distributing ('r) of said coils and the diameter of the same (d) being between 0.8 and 2.0.

2. Means according to claim 1, in which the pump comprises several consecutively located coils to cover the required transport distance, the coils suitably being multi-pole connected.

3. Means according to claim 1, characterised in that the outflow opening is so dimensioned that the inner diameter of the outflow tube is between 0.1 f; and 0.3 where p is the resistivity of the melt in ohm mmlm.

4. Means according to claim 1, inwhich inside the coils positioned about the outlet is placed at least one electrically conducting tube in which currents are induced under the influence of the field from the coil, so that heating is achieved in the conducting tube and heat losses from metal standing in the pump are counteracted.

within the a eas:- 

1. Means for regulating the speed of melt flowing out of a container, comprising a multiphase electromagnetic valve pump arranged around an outlet in the container, said outlet being an upwardly directed tube, leading from the lower part of the container to a level below the highest possible melt level in the container, said valve pump being arranged around the tube and its coil being fed with multi-phase AC voltage with switchable phase sequence, the direction of the phase sequence being controlled from the output from measuring means for measuring the amount of melt, said valve pump comprising at least two sectioned coils, the ratio between the pole distributing ( Tau ) of said coils and the diameter of the same (d) being between 0.8 and 2.0.
 2. Means according to claim 1, in which the pump comprises several consecutively located coils to cover the required transport distance, the coils suitably being multi-pole connected.
 3. Means according to claim 1, characterised in that the outflow opening is so dimensioned that the inner diameter of the outflow tube is between 0.1 Square Root Rho and 0.3 Square Root Rho where Rho is the resistivity of the melt in ohm . mm2/m.
 4. Means according to claim 1, in which inside the coils positioned about the outlet is placed at least one electrically conducting tube in which currents are induced under the influence of the field from the coil, so that heating is achieved in the conducting tube and heat losses from metal standing in the pump are counteracted. 